Flaxseed Introduction

Flaxseed, also called linseed, is derived from the seeds of the same plant that produces linen (Linium usitatissimum). The Linium usitatissimum plant has supplied linen to ancient cultures for millennia. Its dried seeds and accompanying oil have been used medicinally to treat various ailments including constipation, skin inflammation, stomach, bowel and bladder conditions, chest congestion, and heart problems. Current research is confirming its traditional use, finding that flaxseed may indeed have health benefits ranging from laxative properties, to certain anti-inflammatory, antithrombotic, and anticancer effects. [1-3] The American diet is often deficient in omega-3 fatty acids (type of oil found within flaxseed). The dietary supplementation with flaxseed may have important nutritional benefits.

Flaxseed contains approximately 40 - 60% of the omega-3 essential fatty acid known as alpha-linolenic acid (ALA): 15 - 20% of the omega-6 essential fatty acid, linoleic acid; and varying amounts of the lignan, secoisolariciresinol diglycoside (SDG), or more commonly known as phytoestrogens. Research suggests that flaxseed ALA may relieve inflammation by its conversion in the body, into several anti-inflammatory metabolites including eicosopentaenoic acid (EPA), series-3 prostaglandins, the series-5 leukotrienes, and the series-3 thromboxanes.

ALA may block the production of pro-inflammatory compounds, including; eicosanoids, prostaglandin E2 (PGE2), leukotriene B4 (LTB4), cytokines, tumor necrosis factor-alpha (TNF-alpha), and interleukin-1 beta (IL-1 beta). ALA in cellular walls and membranes can affect membrane fluidity and have important immunomodulating, hormonal, anti-therogenic and anti-inflammatory actions. It is theorized that the flaxseed lignan SDG may have anti-platelet activating factor activity. It may also block some of estrogen‘s cancer-inducing effects by selective estrogen receptor modulating (SERM) activity. [1-3]

Flaxseed Food Sources

Parts Used

Dried seeds / Oil

Flaxseed Uses

Flaxseed may be used to support cardiovascular health by helping to prevent heart attack and stroke; and by lowering platelet aggregation, cholesterol, and blood pressure. Although many cardiovascular studies primarily feature only the fish oils EPA and DHA (omega-3 fatty acids), flaxseed may produce similar benefits due to its high concentrations of ALA omega-3 fatty acids which convert to EPA in the body. [3-12] Some studies suggest that the flaxseed lignan SDG may offer additional cardiovascular benefits, by demonstrating anti-platelet activating factor activity. In studies concerning flaseed lignan, up to a 69% reduction in hypercholestemic atherosclerosis was witnessed with flaxseed-enriched diets. [10-12]

  • Flaxseed ALA and lignan SDG may have anticancerous properties. Studies have indicated that flaxseed ALA and lignan SDG may assist in the prevention of breast cancer. [13-16] One study of 121 breast cancer patients found that low levels of ALA were the most significant contributor to the spread of this form of cancer. [13] Other studies have labeled flaxseed lignans as protective factors against breast cancer in women. They have demonstrated the ability to block some of estrogen‘s cancer-inducing effects by means of selective estrogen receptor modulating (SERM) activities. [2, 14, 15] Experimental animal studies suggest that flaxseed may also have anticancer effects for prostate and colon cancers. [17-19]
  • Flaxseed may be used for its anti-inflammatory benefits in conditions such as arthritis. Some studies suggest that flaxseed supplementation may reduce the inflammatory symptoms associated with arthritis. [3, 20]
  • Flaxseed lignan SDG, similar in structure to endogenous sex steroid hormones, may have beneficial hormonal actions in women. One study in particular found a decrease in serum concentrations of 17 beta-estradiol and estrone sulfate, with an increases of prolactin in 28 postmenopausal women when treated with flaxseed-containing supplements. [21]

Flaxseed Dosages

Dosage: Regarding the personal administration of flaxseed oils, there have been no established dosages. Doses are largely dependant upon the conditions being treated. However, it is often recommended to take 1 - 2 tablespoons of a given oil-based product daily. For flaxseed capsules, it is recommended to take the given product as directed by manufacturer. The least popular delivery method, seeds, are ground and mixed with either food or water in amounts equaling 1 tablespoon daily. It is important to note that large quantities of flaxseed taken with too little liquid can cause obstruction of the bowel. [1-3, 27, 28]

Delivery Forms: Oil, capsules, and ground seeds.

Flaxseed Toxicities and Contraindications

Flaxseed should not be taken by those individuals with hemophilia, bowel obstruction, narrowing of the digestive tract, or inflammation of the stomach or intestines. [1-2, 27] 

Pregnant and lactating women, as well as children, should not take or be administered supplemental flaxseed, unless recommended by a health care provider. Flaxseed should not be taken at least 14 days prior to any type of surgery or dental work.

Side effects may include mild diarrhea and bowel obstruction if flaxseed is taken with too little fluid.

Due to its potential drug interactions, individuals should avoid combining flaxseed with the following medications and nutritional supplements:

  • Nonsteroidal anti-inflammatory medications (NSAIDs)
  • Aspirin
  • Warfarin
  • Bile acid sequestrants
  • Orlistat
  • Olestra containing products
  • Chitosan
  • Mineral oil
  • Fish oils

Always inform your health care provider about the dietary supplements you are taking, as there may be a potential for side effects, interactions, or allergy.


1. Flaxseed, PDR Health:


2. Flaxseed Oil, PDR Health:


3. Murray MT. Encyclopedia of Nutritional Supplements, NY: Three Rivers Press, 1996: 252-267.

4. Lucas EA, Wild RD, Hammond LJ, Khalil DA, Juma S, Daggy BP, et al. Flaxseed improves lipid profile without altering biomarkers of bone metabolism in postmenopausal women. J Clin Endocrinol Metab. Apr2002;87(4):1527-32.

5. Kinsella JE, et al. Dietary n-3 Polyunsaturated Fatty Acids and Amelioration of Cardiovascular Disease: Possible Mechanisms. Am J Clin Nutr. Jul1990;52(1):1-28.

6. Garg ML, et al. Alpha-linolenic Acid and Metabolism of Cholesterol and Long-chain Fatty Acids. Nutrition. Jun 1992;8(3):208-10.

7. Knapp HR, et al. The Antihypertensive Effects of Fish Oil. A Controlled Study of Polyunsaturated Fatty Acid Supplements in Essential Hypertension|Hypertension]]. N Engl J Med. Apr1989;320(16):1037-43.

8. Allman MA, Penna MM, Pang D. Supplementation with flaxseed oil versus sunflower seed oil in healthy young men consuming a low fat diet: effects on platelet composition and function. Eur J Clin Nutr. 1995; 49:169-178.

9. Fisher S, Honigmann G et al. Results of linseed oil and olive oil therapy in hyperlipoproteinemia patients. [Article in German]. Dtsch Z Verdau Stoffwechselkr. 1984; 44:245-251.

10. Prasad K, Mantha SV, Muir AD, Westcott ND. Reduction of hypercholesterolemic atherosclerosis by CDC-flaxseed with very low alpha-linolenic acid. Atherosclerosis. 1998; 136:367-375.

11. Prasad K. Dietary flaxseed in prevention of hypercholesterolemic atherosclerosis. Atherosclerosis. 1997; 132:69-76.

12. Rozanova IA, Pogozheva AV, Kupakova SN, et al. Effect of anti-atherosclerotic diet, containing polyunsaturated fatty acids of the omega-3 family from flax oil, on fatty acid composition of cell membranes of patients with ischemic heart disease, hypertensive disease and hyperlipoproteinemia. [Article in Russian]. Vopr Pitan. 1997; (5):15-17.

13. Bougnoux P, et al. Alpha-linolenic acid content of adipose breast tissue: A host determinant of the risk of early metastasis in breast cancer. Br J Cancer 1994 (70): 33-334

14. Tou JC, Thompson LU. Exposure to flaxseed or its lignan component during different developmental stages influences rat mammory gland structures. Carcinogenesis. 1999; 20:1831-1835.

15. Adlercreutz H, et al. Determination of urinary lignans and phytoestrogen metabolites, potential antiestrogens and anticarcinogens, in urine of women in various habitual diets. J Steroid Biochem 1986 (25) 791-797

16. Bagga D, et al. Dietary Modulation of Omega-3/Omega-6 Polyunsaturated Fatty Acid Ratios in Patients with Breast Cancer. J Natl Cancer Inst. Aug 1997;89(15):1123-31.

View Abstract

17. Pandalai PK, et al. The Effects of Omega-3 and Omega-6 Fatty Acids on in Vitro Prostate Cancer Growth. Anticancer Res. Apr1996;16(2):815-20.

18. Anti M, et al. Effect of Omega-3 Fatty Acids on Rectal Mucosal Cell Proliferation in Subjects at Risk for Colon Cancer. Gastroenterology. Sep1992;103(3):883-91.

19. Serraino M and Thompson LU. Flaxseed supplementation and early markers of colon carcinogenesis. Cancer Letters 1992 (63):159-165.

20. Geusens P, et al. Long-term Effect of Omega-3 Fatty Acid Supplementation in Active Rheumatoid Arthritis. A 12-month, Double-blind, Controlled Study. Arthritis Rheum. Jun1994;37(6):824-29.

21. Hutchins AM, Martini MC, Olson BA, Thomas W, Slavin JL. Flaxseed consumption influences endogenous hormone concentrations in postmenopausal women. Nutr Cancer. 2001;39(1):58-65.

22. Stevens L, Zentall SS, Deck JL. Essential fatty acid metabolism in boys with attention-deficit hyperactivity disorder. Am J Clin Nutr. 1995;62:761-768.

23. Galland L. Increased Requirements for Essential Fatty Acids in Atopic Individuals: A Review with Clinical Descriptions. J Am Coll Nutr. 1986;5(2):213-28.

24. Masuev KA. The Effect of Polyunsaturated Fatty Acids of the Omega-3 Class on the Late Phase of the Allergic Reaction in Bronchial Asthma Patients. Ter Arkh. 1997;69(3):31-33.

25. Isseroff RR. Fish Again for Dinner! The Role of Fish and other Dietary Oils in the Therapy of Skin Disease. J Am Acad Dermatol. Dec1988;19(6):1073-80.

26. Hibbeln JR, et al. Dietary polyunsaturated fatty acids and depression: when cholesterol does not satisfy. Am J Clin Nutr. Jul1995;62(1):1-9.

27. Flaxseed, Dietary Supplement Information Bureau:


28. Weil A. 8 Weeks To Optimum Health, NY: Knopf, 1997: 52


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